
Creating a blank disk image
You can use Disk Utility to create a blank disk image to store files. Usually, when you create a disk image, you gather the files you want to include into a single location before you create the disk image. With a blank disk image you can add files to the image over a period of time.
When you create the disk image, you choose a format for the image:
- To create a disk image that uses the same amount of disk space specified for the image, choose "read/write disk image."
- To create a disk image that uses only as much space as required to hold the data placed in the image, choose "sparse disk image."
For example, if you create a 10 MB sparse disk image, then copy only 5 MB of data to the disk image, the image will use only 5 MB of space on your hard disk. If you create a standard disk image, then it will always take the full 10 MB of space on your hard disk.
- In Disk Utility, choose File > New > Blank Disk Image or click New Image.
- Type a name for the disk image and select where you want to save it.
- Choose the size of the disk image from the Size pop-up menu.
- To require a password to access the contents of the disk image, choose "AES-128 (recommended)" from the Encryption pop-up.
- Choose a format from the pop-up menu.
- Click Create.
To add files to the disk image, open the image in the Finder, then drag files to it.